SpringBoot启动器
引入spring-boot-starter-web会自动导入web环境下所有必需的依赖。spring-boot-starter启动器中存放的依赖如下：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>2.2.1.RELEASE</version>
</dependency> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot</artifactId>
<version>2.2.1.RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-aut